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Patricia Headed and Janice Murray Responsibility: Janice Murray AIM To implement theoretical knowledge about experimental design. Key Words: Hypothesis, independent variable, dependent variable, confounding, matching, random assignment, demand characteristics. Introduction For this assignment, you are going to design a psychological experiment! The topic of the proposed piece of research is Visualization Practice and you will test the theory that practicing a skill in your imagination – visualizing yourself performing refectory – Improves performance of the skill.
This Is a widespread theory which has given rise to Its own brand of popular psychology, psycho-cybernetics. Some adherents even suggest that visualization practice results In greater performance improvement than actual practice of the skill. You will design an experiment to evaluate the relative effectiveness of visualization practice and actual practice for improving one’s tennis serve. That is, we want you to design a study to Investigate whether a player’s tennis serve improves with practice, and, particularly, whether It Improves more with visualization practice Han with actual physical practice.
Answer the questions in bold below that will reveal your experimental design. Number your responses and adhere to the “length of response” directions provided with each question in parentheses. Please note we will not accept extraordinarily long sentences! Don’t forget to provide your name, student number, and homework title on the front page. 1. RESEARCH HYPOTHESIS -? you need to start with an hypothesis. It needs to be specific and clear. For example, “Visualization practice can be good” is not definite enough.
You need to specify that participants in one condition (and which one) will show higher test scores than participants in another condition. If you have more than results. What is your research hypothesis? (1-2 sentences). 2. INDEPENDENT VARIABLE -? manipulated variable. This is sometimes called the treatment variable or the Here is an unrelated example of an independent variable in an experiment. If you wish to see if a certain “memory enhancing” drug works on rats, you might give different doses to some rats and then test their memory by testing how quickly the tats learn a new route through a maze.
The independent variable is the one you manipulate (alter between your experimental groups) and in this case would be “drug dose. ” Deciding on your specific independent variable is important. If you decided to have three groups, one receiving O MGM of the drug, one group 15 MGM and the third group 30 MGM, you are said to have three “levels” of your independent variable. The O MGM group, who received no drug, is called your “control group. ” Now, think back to the purpose of this assignment. A) What is the variable you are going to manipulate? (1 -2 sentences). ) Describe the levels of your independent variable (at least two, of course). 2-3 sentences). Be very specific and describe each level. For example, “Group 1 will be told to practice tennis in the following manner for the following period of time . Group 2 will be told … ” Make sure your research hypothesis covers the expected results of all your groups. 3. Outline how you will recruit and select participants and assign them to your experimental groups (3-4 sentences). You can either have the same people in each group (a “within-subjects” design) or different people in each group (a “between- objects” design). You need to be careful with a “within-subjects” design. Why? (2-3 sentences) 4.
CONFOUNDING VARIABLES -? it important that no OTHER variable changes between your experimental groups along with the independent variable. Any other variable that changes is called a confound or a confounding variable. The presence of even a single confounding variable can mean your research is wasted. As another unrelated example, suppose you are interested in the effect of age on memory in young children. Let’s say you wish to compare how 2-year-old and 4-year-old children remember an event. You could take two groups of children, one of each age group, expose all of them to an identical event, and question them later to examine recall.
The four-year-olds would tell you much more about the event than would the two- two groups recalled the event identically, 4-year olds would typically talk more at the interview, thus leading you to conclude (with no real evidence) that 4-year-olds have better memory than 2-year-olds. Describe one potential confounding variable (3-4 sentences) and how you would eliminate it (4-5 sentences). 5. DEPENDENT VARIABLE -? your dependent variable is sometimes called a assured variable, and it refers to the way in which you measure the results in your experiment.